Wednesday, 28 August 2013

Co2 Injection or DIY co2 or No Co2?? Excel only?

Anyone who wanted to start a planted tank will read up about co2, does your tank really need co2 injection? can i do without it?

Co2 is required as the carbon element is required for plant growth. All Plants need carbon or co2 in some form, like it or not, they need co2 to breath.. however with careful selection of plants, you may skip it as low tech plants requires less co2 than high/mid tech plants.

So what are the difference?

With Co2 injection ( proper Co2 setup):-
Pro and Cons

  • Expensive but cheap in long run
  • the setup occupies a lot of space and a bit ugly if its not 
  • can use with diffuser as its pressurized
  • your plants will grow fast, 
  • your plants may start to pearl if the condition is right. ( )
  • to maximise plant growth, you may add more fertiliser/light and 
  • you may need to trim your plants more often
  • you may experience some algae growth due to imbalance of a demand and supply issue
  • if you stop co2 suddenly, you may experience sudden algae bloom as plants will be stunt and algae will take over
  • can use with solenoid and turn it ON and OFF... less hassle and saves co2

Using DIY Co2:- mostly  will be using yeast + sugar water to get the Co2
Pro and Cons

  • Cheap but not efficient 
  • Not exactly eye candy to look at if you display it
  • can't be used with certain co2 diffusser due to low pressure
  • You may have some fast co2 production initially and almost zero production around 2 weeks down the road, so you need to change the mixture every 2 weeks ( i tested it, not doing it anymore)
  • Unstable Co2 production, may lead to Black Brush Algae.. ugly
  • The mixture smells like alcohol...well, that is the by product anyway, so Muslim friends might not like it.
  • not for lazy people aka yours truly

Using Seachem Excel as carbon substitute
Pros and Cons

  • Expensive in long run
  • Half life is around 12hours, so it will be breakdown after 24 hours of exposing to light
  • its algaecide:- stops/kills algae... but may kill your fauna/flora if overdosed/unproper usage ( WARNING)
  • easy to dose
  • no hassle, won't occupy a lot of space.
  • good for low tech tanks, not for high tech plants unless you use it to control algae growth
  • good for lazy + poor people...aka people like yours truly

USING Co2 tablets

You are kena CONNED .. skip these tablets..waste of your time
the lfs or salesman can tell you all those grandmother story about how good it is.. well believe me dude.. you are better off with dosing Seachem excel..similar cost anyway


So does your aquarium needs co2 injection? it really depends on WHAT YOU WANT BRADER!!
Careful selection of plant, you may skip it,
if you are into a green most probably need a proper setup as more lawn like plants need good nutrient,high light, good temperature ( 25-29dc),constant supply of co2 to grow nice... 

Disclaimer:- some people might say "I kept XXX plant without CO2, and it grows nice + lawn nicely" well, i admit some people have green fingers, i can't say they are bluffing or they add some snake oil into the aquarium but you may not have green finger like them, so you are better off staying on the " traditional" way of planting. 


  1. I feel that seachem excel is not exactly a CO2 replacement.

    I would recommend CO2 injection either through a DIY bottle or tank. its either that, or none.

    1. some excel is better than none leh bro... can help to control algae also...:)

  2. Great writeup! Funny too especially the CO2 Tablets part. LOL
    For a 2 ft tank with high lighting and demanding plants like HC, what in your opinion would be the number of C02 bubbles/sec? I dont have a Co2 test kit to find out thats why

  3. For hc, 3-4wpg light with moderate co2 is recommended

    Bps is not accurate, drop checker is better. As long it shows green colour your are quite ok.

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